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Stetsonguy
09-24-14, 14:51
Hello everybody I'm new here and thought I would say Hi first of all.

I have a question maybe y'all can help me with that I wasn't able to find information on.

If you have an 18" barrel on your AR, what is the best gas length for it. I've heard either mid or rifle length
would work...but then again I've heard that both suck for that barrel. Which is it?

And I don't suppose there exists a "semi" rifle length gas system.. somewhere in between mid and rifle.
thopkins22
09-24-14, 14:58
And I don't suppose there exists a "semi" rifle length gas system.. somewhere in between mid and rifle.

Intermediate, and to me it makes the most sense for 18". Available here...I'm sure others make one too if you look hard enough. http://www.shopnoveske.com/collections/barrels/products/lightweight-5-56mm-stainless-barrel

But mid length 18" systems will run just fine, as will rifle length...provided of course that they are made and assembled properly. It's all a balance between too little gas and too much gas and there's no such thing as perfect for everything.
bruin
09-24-14, 16:37
I find the approach Sionics took to be interesting: 18.5" rifle gas. That extra half inch supposedly helps with reliability. Perhaps IG can comment on this.

You can also emulate a longer barrel with a muzzle device that has an expansion chamber. I know that was a discussion on this in the last few months. If your gas system is too short however, there's not much you can do about it.
Clint
09-24-14, 18:01
On an 18" 5.56, the intermediate length gas is ideal.

Rifle and mid can both work, but are not as balanced as INT.

As always, proper gas port size is critical.
Onyx Z
09-24-14, 22:56
I prefer intermediate over rifle. As far as I know, Novekse and Rainier Arms are the only two manufacturer that make intermediate gas systems though.
teutonicpolymer
09-24-14, 23:22
I like rifle length for 18"
bp7178
09-25-14, 00:14
Rifle with a Sprinco blue buffer spring and a H2 buffer. Super soft and has been very reliable for me.
SanChoLee
09-25-14, 00:49
My 18" Rainier match barrel with the rifle length gas is treating me just fine. I'm very happy with it. Can't comment on the intermediate but it was the other option I was looking at.
RyanB
09-25-14, 01:11
Why do you have a preference for intermediate? I've had a number of rifle length 17-18" barrels that served me well and I have an intermediate barrel now that I've yet to fire.
BufordTJustice
09-25-14, 08:22
My Rainier Arms Mountain Series 18" with rifle gas has an adjustable gas block turned down to about 50% restriction, and I'm running the Vltor A5 system with an A5H2 buffer.

Runs on shitty steel cased and PMC bronze. Just my experience.
docsherm
09-25-14, 09:44
I like rifle length with a rifle buffer system. It is very smooth and reliable.
Stetsonguy
09-25-14, 11:28
Thanks for the replies. I didn't even know the intermediate system existed. I just thought there were three.
carbine, mid, and rifle
TehLlama
09-25-14, 13:08
Rifle, Intermediate, (KAC Intermediate), Midlength, Carbine, Pistol - there is a fair bit of diversity possible, and oddly 18" can use four of those quite well.

I'm partial to my Rifle length 18" units, simply because they're more than smooth enough with A2 or A5 receiver extension and buffer setups, and are comparably happy when ran suppressed.
Iraqgunz
09-25-14, 15:53
Our SIONICS barrels are now 18" and we use the same gas port as spec'd for the SPR. This is the same barrel we used in the Axelson Tactical AXE rifle. You can see video of Marcus Luttrell and Ron Bellan shooting it. It shoots exceptionally well and even smoother with the A5.
ghostsup
09-25-14, 19:16
Our SIONICS barrels are now 18" and we use the same gas port as spec'd for the SPR. This is the same barrel we used in the Axelson Tactical AXE rifle. You can see video of Marcus Luttrell and Ron Bellan shooting it. It shoots exceptionally well and even smoother with the A5.

I don't see them listed in your "Barrels" section on your site.
Metric Matt
09-25-14, 20:58
I have an upper I built with an FN CHF 18" rifle length barrel, and use an H2 buffer. It shoots very smooth and has eaten everything I've thrown at it, 55gn, 62gn, 77gn 5.56 and even some shitty steel case .223 with no problems.
Iraqgunz
09-25-14, 23:18
We dedicated our remaining inventory to Axelson Tactical to build their rifles. We are also looking at some different barrel choices and options which is why they are not listed.

http://vimeo.com/104638209


I don't see them listed in your "Barrels" section on your site.